U.S. patent number 5,703,464 [Application Number 08/495,984] was granted by the patent office on 1997-12-30 for radio frequency energy management system.
This patent grant is currently assigned to Amerigon, Inc.. Invention is credited to David A. Bell, Tissa R. Karunasiri, Bruce M. Ryan.
United States Patent |
5,703,464 |
Karunasiri , et al. |
December 30, 1997 |
Radio frequency energy management system
Abstract
A radio frequency energy management system includes a number of
battery control modules and an control unit, each configured to
transmit and receive radio frequency signals comprising information
relating to the operating parameters of batteries in a battery
pack, and control commands for regulating the operating parameters
of such batteries. Each battery control module is configured to
monitor one or more operating parameter of a respective battery,
and to regulate one or more operating parameter according to a
control system program in the control unit. Each battery control
module includes one or more sensing elements to measure one or more
operating parameter of a respective battery, a radio frequency
receiver, and a radio frequency transmitter. The control unit is
configured to monitor and control the operating parameters of the
batteries and includes a radio frequency receiver, configured to
receive a radio frequency signal transmitted by the radio frequency
transmitter in each battery control module, and a radio frequency
transmitter configured to transmit a radio frequency signal capable
of being received by the radio frequency receiver in each battery
control module. The control unit evaluates data transmitted from
each battery control module according to a predetermined control
system program, and transmits a predetermined control command to
one or more battery control module to achieve battery equalization.
Radio frequency signals are transmitted between the control unit
and each battery control module without additional wiring, thereby
eliminating the disadvantages of wired-type systems.
Inventors: |
Karunasiri; Tissa R. (Van Nuys,
CA), Bell; David A. (Altadena, CA), Ryan; Bruce M.
(West Hills, CA) |
Assignee: |
Amerigon, Inc. (Irwindale,
CA)
|
Family
ID: |
23970779 |
Appl.
No.: |
08/495,984 |
Filed: |
June 28, 1995 |
Current U.S.
Class: |
320/125;
180/65.8; 320/119; 340/310.11; 310/51; 340/12.32 |
Current CPC
Class: |
B60L
58/18 (20190201); B60L 58/22 (20190201); H02J
7/0022 (20130101); H02J 7/0021 (20130101); B60L
8/003 (20130101); H02J 13/00002 (20200101); B60L
58/25 (20190201); H02J 7/0016 (20130101); B60L
3/0046 (20130101); H02J 13/0003 (20130101); Y02T
90/16 (20130101); Y02T 90/14 (20130101); Y02T
10/70 (20130101); Y02T 10/7072 (20130101); B60L
2250/10 (20130101); Y02T 90/12 (20130101) |
Current International
Class: |
B60L
11/18 (20060101); H02J 7/00 (20060101); H02J
13/00 (20060101); H01M 010/44 () |
Field of
Search: |
;320/2,5,15,16,17,18,19,48 ;310/59,220 ;363/46,47 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Wong; Peter S.
Assistant Examiner: Toatley, Jr.; Gregory J.
Attorney, Agent or Firm: Christie,Parker & Hale LLP
Claims
What is claimed is:
1. An energy management system for use with an electrically powered
apparatus, the system comprising:
a number of battery control modules on the apparatus, wherein each
battery control module includes:
means for monitoring an operating parameter of an electric power
source for the apparatus selected from the group consisting of a
battery pack, at least one battery in a battery pack, at least one
cell in a battery, and combinations thereof;
means for receiving a radio frequency signal;
means for transmitting a radio frequency signal; and
a control unit on the apparatus configured to monitor and control
the battery control modules by radio frequency signal, wherein the
control unit includes:
means for receiving a radio frequency signal transmitted from each
battery control module; and
means for transmitting a radio frequency control signal to each
battery control module;
wherein the receiving and transmitting means for the control unit
and each battery control module is connected to a common conductive
transmission medium disposed between the electric power source and
a power handling device in the electrically powered apparatus.
2. An energy management system as recited in claim 1 wherein the
control unit further comprises means for evaluating radio frequency
signals transmitted by each battery control module and providing a
control signal to transmit to at least one designated battery
control module.
3. An energy management system as recited in claim 1 wherein the
control unit further comprises means for addressing the control
signal to one or more designated battery control module.
4. An energy management system as recited in claim 3 wherein each
battery control module further comprises means for recognizing
whether a control signal is addressed to that particular battery
control module.
5. An energy management system as recited in claim 1 wherein the
means for transmitting radio frequency signals for each battery
control module and the control unit is a radio frequency
transmitter, and wherein the radio frequency transmitter in each
battery control module is configured to transmit a radio frequency
different from that of the radio frequency transmitter in the
control unit.
6. An energy management system as recited in claim 5 wherein the
means for receiving radio frequency signals for each battery
control module and the control unit is a radio frequency receiver,
wherein the radio frequency receiver in each battery control module
is configured to receive radio frequency control signals
transmitted from the control unit, and wherein the radio frequency
receiver in the control unit is configured to receive radio
frequency signals from each battery control module.
7. An energy management system as recited in claim 1 wherein each
battery control module comprises a battery voltage monitoring
element and a battery temperature monitoring element, each attached
to the electric power source.
8. An energy management system as recited in claim 1 wherein each
battery control module is configured to transmit energy source
operating parameter information in response to a designated control
signal.
9. An energy management system as recited in claim 1 wherein each
battery control module further comprises means for controlling at
least one energy source operating parameter that is activated in
response to a designated control signal.
10. An energy management system as recited in claim 1 further
comprising means for isolating the radio frequency signals
transmitted and received by each battery control module and the
control module from other electrical devices in the electrically
power apparatus.
11. An energy management system as recited in claim 1 further
comprising a second control unit located off of the electrically
powered apparatus, wherein the second control unit includes means
for receiving radio frequency signals from the control unit and the
battery control modules, and means for transmitting radio frequency
control signals to the control unit and battery control
modules.
12. An energy management system as recited in claim 1 wherein the
second control unit is adapted to accommodate attachment with a
user interface.
13. An energy management system as recited in claim 1 wherein the
control unit includes means for storing electric power source
operating parameter information transmitted by each battery control
module.
14. An energy management system for use with an electric vehicle
having a battery source of motive power, the system comprising:
a number of battery control modules, wherein each battery control
module includes:
at least one monitoring element located on the vehicle and
configured to measure an operating parameter of an electric power
source selected from the group consisting of a battery pack, at
least one battery in a battery pack, at least one cell in a
battery, and combinations thereof;
a radio frequency receiver;
a radio frequency transmitter; and
a control unit located on the vehicle and configured to monitor and
control the battery control modules by radio frequency signal,
wherein the control unit includes:
a radio frequency receiver configured to receive a radio frequency
signal transmitted from the radio frequency transmitter in each
battery control module;
a radio frequency transmitter configured to transmit a radio
frequency signal that is capable of being received by the radio
frequency receiver in each battery control module;
means for evaluating radio frequency signals received from each
battery control module and providing a control signal to transmit
to at least one designated battery control module;
wherein the radio frequency receiver and transmitter for the
control unit and each battery_ control module is connected to a
common conductive .path attached between the electric power source
and a power handling device in the vehicle.
15. An energy management system as recited in claim 14 wherein the
control unit includes means for addressing the control signal to be
recognized by at least one designated battery control module.
16. An energy management system as recited in claim 15 wherein each
battery control module includes means for recognizing whether a
control signal is addressed to that particular battery control
module.
17. An energy management system as recited in claim 14 further
comprising means for isolating the radio frequency signals
transmitted and received by each battery control module and the
control module via the conductive path from other devices in the
vehicle.
18. An energy management system as recited in claim 14 further
comprising means disposed between the conductive path and the
control unit to isolate the control unit from high-voltage
differentials between the conductive path and the control unit.
19. An energy management system as recited in claim 14 wherein each
battery control module includes a battery voltage monitoring
element and a battery temperature monitoring element.
20. An energy management system as recited in claim 14 wherein each
battery control module is configured to transmit energy source
operating parameter information in response to a designated control
signal.
21. An energy management system as recited in claim 20 wherein each
battery control module further comprises means for effecting a
change in at least one energy source operating parameter in
response to a designated control signal.
22. An energy management system as recited in claim 14 further
comprising means for isolating the radio frequency signals
transmitted and received by each battery control module and the
control module from other electrical devices in the electrically
powered apparatus.
23. An energy management system as recited in claim 14 further
comprising a second control unit located off of the vehicle,
wherein the second control unit includes a radio frequency
transmitter and a radio frequency receiver configured to
accommodate communication with the control unit and each battery
control module.
24. An energy management system as recited in claim 23 wherein the
second control unit is adapted to accommodate connection with a
user interface.
25. An energy management system as recited in claim 14 wherein the
control unit includes means for storing (battery) energy source
operating parameter information transmitted by each battery control
module.
26. An energy management system for use with an electric vehicle
having a battery source of motive power, the energy management
system comprising:
a number of battery control modules located on the vehicle, wherein
each battery control module is configured to transmit energy source
operating parameter information by radio frequency signal in
response to a radio frequency control signal, and wherein each
battery control module includes:
at least one monitoring element for measuring an operating
parameter of a respective battery or a battery cell;
a radio frequency transmitter for transmitting operating parameters
measured by each monitoring element of the battery control
module;
a radio frequency receiver for receiving a control signal; and
a control unit located on the electric powered apparatus for
monitoring and controlling the battery control modules by radio
frequency signal, wherein the control unit includes:
a radio frequency receiver adapted to receive a transmitted signal
from each battery control module;
a controller for evaluating the radio frequency signal transmitted
from each battery control module and providing a control
signal;
means for addressing the control signal to be recognized by one or
more designated battery control module; and
a radio frequency transmitter for transmitting the radio frequency
control signal to each battery control module;
wherein the radio frequency receiver and transmitter for the
control unit and each battery control module is connected to a
common main conductive path in an electrical system of the vehicle
running between batteries in a battery pack and connecting the
battery pack to a power handling device in the vehicle.
27. An energy management system as recited in claim 26 further
comprising a second control unit located off of the vehicle, the
second control unit including:
a radio frequency receiver configured to receive radio frequency
signals from each battery control module and the control unit;
a controller for evaluating the signal transmitted from each
battery control module the control unit and providing a control
signal; and
a radio frequency transmitter configured to transmit the control
signal to the control unit and the battery control modules.
28. An energy management system as recited in claim 27 wherein the
second control unit is adapted to accommodate connection with a
user interface.
29. An energy management system as recited in claim 26 wherein each
battery control module includes means for effecting a change in an
energy source operating parameter in response to a designated
control signal.
30. An energy management system as recited in claim 26 wherein each
battery control module includes means for evaluating whether the
control signal is addressed to that particular battery control
module.
31. An energy management system as recited in claim 26 further
comprising means for isolating radio frequency signals transmitted
and received by the battery control modules and the control unit
from other electrical devices connected to the main conductive
path.
32. An energy management system as recited in claim 26 further
comprising means disposed between the main conductive path the
control unit for isolating the control unit from high-voltage
differentials between the conductive path and the control unit.
33. An energy management system for use with an electric vehicle
having a battery source of motive power, the system comprising:
a number of battery control modules for monitoring and controlling
at least one operating parameter of batteries in a battery pack,
wherein each battery control module is located on the vehicle and
includes:
at least one monitoring element for monitoring an operating
parameter of the battery;
a radio frequency transmitter, wherein the radio frequency
transmitter is configured to transmit battery operating parameter
information in response to a radio frequency control signal;
a radio frequency receiver for receiving a radio frequency control
signal;
means for evaluating the radio frequency control signal to
determine if the control signal is addressed to that particular
battery control module; and
a control element for effecting a change of at least one operating
parameter of the battery in response to a designated radio
frequency control signal;
a control unit for evaluating battery operating parameter
information transmitted by radio frequency from each battery
control module and producing a designated radio frequency control
signal to control the battery control modules, wherein the control
unit includes:
a radio frequency receiver configured to receive radio frequency
signals transmitted by each battery control module;
means for evaluating information received from each battery control
module and for producing a designated radio frequency control
signal;
means for addressing the radio frequency control signal to be
recognized by one or more designated battery control module;
and
a radio frequency transmitter for transmitting the control signal
to the battery control modules; and
a main conductive path in an electrical system of the vehicle
connecting the batteries in the battery pack to a power handling
device in the vehicle, wherein the radio frequency receiver and
transmitter for the control unit and each battery control module
are connected to the main conductive path for transmitting radio
frequency signals therebetween.
34. An energy management system as recited in claim 33 wherein each
battery control module includes a battery voltage monitoring
element and a battery temperature monitoring element.
35. An energy management system as recited in claim 33 wherein the
control element is a switch adapted to discharge a respective
battery through a shunt resister in response to a designated
control signal.
36. An energy management system as recited in claim 33 further
comprising means disposed between the main conductive path and the
control unit for isolating the control unit from high-voltage
differentials between the main conductive path and the control
unit.
37. An energy management system as recited in claim 33 further
comprising means disposed between the main conductive path and
other electrical devices in the electric vehicle for isolating the
radio frequency signals of the energy management system such other
devices.
38. An energy management system as recited in claim 33 further
comprising a second control unit located off of the vehicle,
wherein the second control unit includes a radio frequency
transmitter and a radio frequency receiver configured to
accommodate communication with the control unit and each battery
control module.
39. An energy management system as recited in claim 38 wherein the
second control unit is adapted to accommodate connection with a
user interface.
40. An energy management system as recited in claim 33 wherein the
control unit includes means for storing battery operating parameter
information transmitted by each battery control module.
41. An energy management system as recited in claim 39 wherein the
second control unit is manufactured as part of a battery charger
located off of the vehicle.
42. An energy management system as recited in claim 33 wherein the
control unit is manufactured as part of a battery charger located
on the vehicle.
43. An energy management system as recited in claim 33 wherein the
control unit is manufactured as part of a motor controller on the
vehicle.
44. An energy management system as recited in claim 33 wherein each
battery control module is manufactured as part of battery source of
motive power.
Description
FIELD OF THE INVENTION
This invention relates to energy management systems for monitoring
and controlling electrical power sources and, more particularly, to
an energy management system for monitoring and controlling electric
batteries or battery cells in a battery pack used to power electric
vehicles by use of radio frequency data and control signal
transmission.
BACKGROUND OF THE INVENTION
Energy management systems for monitoring and controlling the
operation of electrical devices in conventional hydrocarbon powered
vehicles are known in the art. Such systems may include one or more
device located near the particular electrical device to be
monitored and controlled. These devices perform the desired
monitoring or control functions in response to control signals
provided by a central control unit or "brain". The central control
unit is typically mounted at a location within the vehicle remote
from the devices and is electrically connected to the device by a
wiring harness. The control unit may include a processing system
that processes any input signals received from the devices and
transmits output signals to the devices to perform a specific
control function. The processing system may be driven according to
a specific control system program.
In conventional hydrocarbon powered vehicles, energy management is
an ancillary feature that allows the vehicle's electrical
functions, such as heating and cooling of the passenger
compartment, to be performed in a more efficient or more
comfortable manner. Such an energy management system may also
operate to optimize the operation of the engine under particular
conditions to improve engine efficiency or performance.
However, in electrically powered vehicles, energy management is not
an ancillary feature but is a primary feature that is useful in
monitoring and controlling the performance of the power source
itself. In order to obtain maximum operating efficiency of an
electrically powered vehicle, it is desired that the particular
electric power source be controlled in such a manner to derive its
maximum output capacity under a variety of different operating
conditions. Accordingly, it is desired that energy management
systems useful in electric powered vehicles, rather than monitor
and control accessory electrical functions such as passenger
compartment cooling and heating, operate primarily to monitor and
control operating parameters of the power source itself, e.g.,
battery or battery cell voltage.
Energy management systems that are used with electrically powered
vehicles to monitor and control the electric batteries, or
individual cells in the batteries, used to power an electric
vehicle, are known in the art. Such energy control systems are
similar to those discussed above for use with hydrocarbon powered
vehicles, in that such systems typically include one or more
monitoring device and a central control unit. The monitoring
devices are positioned near a particular battery or battery cell,
and the central control unit is positioned within the vehicle at
some remote location. Each monitoring device is connected to the
central control unit by wired connection, typically by use of a
wire harness, to facilitate transmission of information to and from
the monitoring modules and the central control unit. The central
control unit is configured to receive data from the monitoring
devices, process the data, and produce control signals to the
monitoring devices to effect a desired change in battery or battery
cell operation.
In such systems, control signals are passed from the central
control unit to a monitoring device, and information is passed from
the monitoring devices to the central control unit through wires
that run through the vehicle and connect each monitoring device
with the central control unit. The wires can either be bundled
together and routed along a primary wire harness for the vehicle's
electrical system, or may routed separately from the primary wire
harness.
A wire-type energy management system for monitoring and controlling
operating parameters of an energy source in an electric powered
vehicle is not desirable for a number of reasons. The use of wires,
in addition to those already in the vehicle's electrical system,
can add as much as fifty pounds to the weight of the vehicle. Such
added weight can decrease the vehicle's acceleration and increase
battery charge frequency. The use of a wire-type energy management
system also increases the manufacturing cost of the vehicle, due
both to the time associated with installing the additional wiring
and the cost of the wire itself. The use of a wire-type energy
management system also increases the cost of maintaining the
system, because of the proximity of the wires connecting the
monitoring devices to the batteries and resulting corrosion damage
that is likely to occur. Such corrosion damage adversely effects
the reliability and service life of a wire-type energy management
system.
Additionally, the use of a wire-type energy management system
requires use of high-voltage isolation components to reduce system
interference or noise that may occur in signal wires from
high-voltage wires that are typical of electric vehicle battery
packs in the vehicle's electrical system. The use of such
high-voltage isolation components both increases the manufacturing
cost of the electric vehicle and increases vehicle weight. A
wire-type energy management system is also limited in terms of
future component upgrades, because of the need to provide
additional wiring for each new upgraded component.
It is, therefore, desirable that an energy management system for
use with an electric powered vehicle be constructed having multiple
system devices capable of communicating with a central control unit
in a wireless manner that does not add weight to the vehicle, is
not vulnerable to battery corrosion, is easy and quick to install,
does not require the use of high-voltage isolators, and that
facilitates any upgrading or adding of new devices without
modification. It is desirable that such an energy management system
be configured having devices that are capable of being used to
monitor and control one or more batteries or the battery cells of
each such battery to provide battery equalization and, thereby
optimize the performance of a battery pack comprising such
batteries. Particularly, it is desirable that the energy management
system be configured to permit the detection of battery or battery
cell changes and to permit tracking individual battery
characteristics.
SUMMARY OF THE INVENTION
There is, therefore, provided in the practice of this invention a
wireless radio frequency energy management system for use in an
electrically powered apparatus such as an electric vehicle having a
battery source of motive power. The energy management system
includes a number of battery control modules and a control unit.
Each battery control module is configured to transmit radio
frequency signals that carry information relating to the operating
parameters of an electric power source, e.g., a battery pack,
individual batteries in a battery pack, or battery cells in
batteries making up a battery pack. The control unit is configured
to receive such signals and transmit to the battery control modules
control signals for regulating the operating parameters of such
power source.
Each battery control module is configured to monitor one or more
designated operating parameter(s) of the power source, and to
control or regulate one or more operating parameter(s) according to
a designated control signal received from the control unit. Each
battery control module includes one or more monitoring or sensing
element(s), each configured to measure a designated operating
parameter of the power source. Each battery control module also
includes a radio frequency receiver and a radio frequency
transmitter. Each battery control module is configured to transmit
battery operating parameter information to the control unit in
response to a control signal.
The control unit is configured to monitor the operating
parameter(s) of the power source measured by the sensing element(s)
in each battery control module, and control the battery control
modules to regulate such operating parameters. The control unit
includes a radio frequency receiver configured to receive a radio
frequency signal transmitted from the radio frequency transmitter
in each battery control module. The control unit also includes a
radio frequency transmitter configured to transmit a radio
frequency control signal that is capable of being received by the
radio frequency receiver in each battery control module.
The control unit evaluates data transmitted from each battery
control module regarding the operating parameter(s) of the power
source, evaluates the data according to a predetermined control
system program, and generates a predetermined control command that
is transmitted as a control signal to the battery control modules.
The control unit addresses the control signal to be recognized by
one or more designated battery control module. In the event that
the power source monitored comprises individual batteries in a
battery pack, the control Unit is programmed to evaluate the
operating parameter(s) of the individual batteries and generate one
or more control signal to effect battery charge equalization,
thereby extending battery pack service life.
Radio frequency signals are transmitted between the control unit
and each battery control module without the use of additional
wiring, by using a main conductive path that runs between the
batteries within a battery pack, through the battery pack, and to a
power handling device of an existing electrical system. The main
conductive path acts as a transmission medium for the radio
frequency signal. By eliminating the need for additional wiring,
wiring harnesses and the like to enable signal transmission, and by
designing the energy management system as a modular construction,
the resulting system is light weight, is not vulnerable to battery
corrosion, is easy and quick to install, facilitates upgrading or
adding of new modules without significant modification, facilitates
easy switching or replacing of batteries or the entire battery
pack, and does not require the use of high-voltage isolators when
compared to existing wired-type systems.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other features and advantages of the present invention
will become appreciated as the same becomes better understood with
reference to the specification, claims and drawings wherein:
FIG. 1 is a schematic diagram of an energy management system
constructed according to principles of this invention comprising a
control unit and a number of battery monitoring modules;
FIG. 2 is a schematic diagram of a battery monitoring module
illustrated in FIG. 1; and
FIG. 3 is a schematic diagram of a control unit illustrated in FIG.
1.
DETAILED DESCRIPTION
An energy management system (EMS) constructed according to
principles of this invention includes a control unit and a number
of battery control modules. The system can be used for monitoring
the performance of, measuring the operating parameters of, and
controlling operating parameters of batteries, battery cells, or
groups of batteries within a battery pack. The system of this
invention can be used with battery packs for electrically powered
devices such as electric vehicles and hybrid electric vehicles
having a battery source of motive power (e.g., military vehicles,
trains, wheelchairs, golf carts and other recreational vehicles,
stackers, forklifts, industrial vehicles, buses, automobiles, and
three wheel drive vehicles), in electrical power-storage
applications (e.g., home emergency, business operation, boat,
aircraft, or satellite power supplies), and in consumer electronic
devices.
Referring to FIG. 1, an EMS prepared according to this invention is
illustrated as installed in an electrical system of an electrically
power device. The electrical system includes a number of batteries
10 that are connected in series to form a battery pack. In the
embodiment illustrated, the battery control modules are shown as
being used with five batteries 10. For use in an electrical system
of an electric vehicle, each battery 10 is a lead-acid battery
having a voltage in the range of from about 10 to 15 volts DC. It
is to be understood that EMSs of this invention are intended to be
used with many different types of batteries, i.e., batteries having
other than lead-acid construction, for example nickel-cadmium,
silver-zinc, lithium polymer, zinc-air, sodium-sulfur and the like.
It is also understood that EMSs of this invention can be used with
batteries configured differently within a battery pack, i.e.,
batteries connected in series, series/parallel, or parallel, than
that specifically described and illustrated in FIG. 1. In addition,
EMSs of this invention can be used with battery packs made up of
identical type of batteries, or battery packs made up of
combinations of different types of batteries, e.g., lead-acid and
nickel-cadmium batteries, lead-acid and zinc-air batteries, lithium
polymer and lead-acid batteries, zinc-air and nickel-cadmium
batteries.
The electrical system of the apparatus also includes a power
handling device 12. In an electric vehicle, the power handling
device is a motor controller 12, which can be a conventional motor
controller used to control the amount and polarity of voltage that
is applied to one or more drive motor 14 used to turn a
corresponding vehicle axle or wheel.
The electrical system of the apparatus includes a main conductive
path or main conductor 16 formed from an assembly of one or more
electrically conductive wires that is used to electrically connect
together the batteries 10, to form a battery pack, and connect the
battery pack with other primary electrical devices in the device.
In an electrically power vehicle, the main conductor 16 is used to
connect the batteries 10 in series connection to form the battery
pack, and is used to electrically connect the battery pack to the
motor controller 12. Accordingly, in an electric vehicle power from
the battery pack is routed via the main conductor 16 to the motor
controller 12 for application to one or more drive motor 14.
An EMS constructed according to principles of this invention
includes a number of battery control modules (BCM) 18 that are each
configured to measure one or more power source operating
parameter(s). As applied in a primary electrical system in an
electric vehicle, each BCM can be used to monitor one or more
operating parameter(s) of a battery pack, batteries in the battery
pack, or battery cells in a battery making up the battery pack. As
installed in an electric vehicle, each BCM is powered by 12 volts
DC, supplied by connection between BCM power leads 20 and
respective positive and negative terminals of an associated battery
10. Alternatively, rather than being powered by a respective
battery, each BCM can be powered by an internal power source, by a
power source on the vehicle other than a respective battery, by
inductive transmission of AC power, by solar power and the
like.
Each BCM 18 of the embodiment of FIG. 1 is configured to monitor
one or more operating parameter(s) of a respective battery 10 in
the battery pack. Accordingly, the number of BCMs used in the EMS
shown in FIG. 1 is the same as the number of batteries 10 that are
used to make up the battery pack, i.e., five. Alternatively, the
BCMs can be used to monitor one or more operating parameter of each
battery cell in the batteries that make up the battery pack, in
which case the number of BCMs used could be greater than the number
of batteries. It is, therefore, to be understood that the BCMs can
be used in a manner other than that specifically described above
and illustrated in FIG. 1.
Additionally, although each BCM 18 is illustrated as being separate
from each respective battery, it is to be understood that each BCM
could alternatively be constructed as part of the battery itself or
as an integral element of the battery. For example, the BCM could
be manufactured within a compartment in the battery housing,
isolated from the electrolytic cells. In such an embodiment, all
outputs from and inputs to the BCM would be connected to respective
battery terminals or other battery inputs or outputs internally
within the battery housing. Alternatively, the BCMs are configured
to be releasibly attachable to a respective battery used in a
battery pack to facilitate both removal, when a battery is removed
from the battery pack, and attachment when the removed battery is
replaced with a new battery. Additionally, where each BCM is
configured to monitor the operating parameters of individual
battery cells, the BCMs are configured to be releasibly attached to
a respective battery cell.
Each BCM 18 is constructed to monitor and measure one or more
designated operating parameter(s) of a respective battery 10. The
particular operating parameter(s) monitored and measured by each
BCM can vary, depending on each particular application, but may
include battery voltage, battery current, battery cell electrolyte
density or specific gravity, specific gravity gradient, electrolyte
level, battery temperature, battery pressure, and combinations
thereof. In one embodiment, each BCM 18 is constructed to monitor
the voltage output and temperature of each respective battery. Each
BCM is configured to transmit operating parameter information to
the control unit in response to a control signal. Each BCM 18 is
also constructed to control designated operating parameters of a
respective battery such as battery voltage, resistance,
temperature, current and the like, in response to a control signal.
In one embodiment, each BCM is constructed control the voltage,
current, or effective resistance of a respective battery within the
battery pack.
A key feature of each BCM is that it is constructed to transmit
information relating to one or more monitored or measured battery
operating parameter using a radio frequency signal rather than by
conventional transmission means, such as by using electrically
conductive wires. Each BCM is constructed to receive an analog
input signal from one or more monitoring element or sensor for a
respective battery, convert the analog signal to a digital signal,
and transmit the signal using a designated radio frequency to an
EMS control unit 22, described in greater detail below. To
facilitate transmission of the radio frequency signal within the
vehicle, the main conductor 16 serves as a transmission medium and
radio frequency inputs and outputs of each BCM 18 and the control
unit 22 are connected thereto. The main conductor 16 acts as a
transmission medium to transmit the radio frequency signal from
each BCM to the EMS control unit without the need to add additional
wiring.
An EMS constructed according to principles of this invention
includes an EMS control unit 22 that comprises a signal conductor
connected to the main conductor 16 for purpose of receiving and
transmitting radio frequency signals to and from each BCM 18. The
control unit 22 is located on board the device or vehicle. The
location of the control unit may depend on a number of different
variables such as available room, battery pack type and the like.
In certain embodiments, the control unit 22 can be manufactured as
part of a power handling device or motor controller 12. The control
unit 22 is constructed to receive battery operating parameter
information from one or more designated BCM, process the
information according to a predetermined control system program,
and transmit monitoring, measuring and/or control instructions to
one or more designated BCM 18.
A key feature of the control unit 22 is that, like the BCMs 18, it
is constructed to receive radio frequency signals transmitted by
each of the BCMs 18 through the main conductor 16. The control unit
22 is constructed to take the input radio frequency signal from
each BCM and convert it to a digital signal. The digital signal is
then sent through a processor, which evaluates the digital signal
according to a control system program and provides a digital output
control signal. The control unit 22 is constructed to take the
digital output signal, convert it to a radio frequency signal, and
transmit the radio frequency signal to one or more designated BCM
18.
To permit communication between the control unit 22 and one or more
designated BCM 18, the control module includes means for encoding
or addressing each output control signal to be recognized by one or
more designated BCM 18. Each BCM is also constructed having
complementary means for reading the control signal to determine
whether the control signal is addressed to that particular BCM.
Constructed in this manner, the control unit 22 is able to transmit
control signals to particular. BCMs in response to information
received from such BCM. Additionally, in alternative embodiments,
each BCM is configured to recognize more than one addressed control
signal, which may also be recognized by more than one BCM, to
permit the control unit to control more than one BCM
simultaneously. This is desirable under certain operating
conditions, such when the energy source or battery pack is cold and
it is desired that a number of BCMs be controlled to heat a number
of batteries in the battery pack and, thereby provide enhanced
performance.
Referring still to FIG. 1, an EMS constructed according to
principles of this invention includes means for insuring that radio
frequency signals between the control unit and each BCM are not
interrupted or disconnected in the event of an open circuit across
a battery. In one embodiment, such means is a capacitor 24 that is
placed across the positive and negative terminals of each
respective battery 10 in parallel electrical connection with the
power leads 20 of a respective BCM. The capacitor provides for the
passage of radio frequency signals across a battery in the event of
an open circuit. Without the use of such capacitors 24, an open
circuit in a battery within the battery pack could cut off radio
frequency transmission between the control unit and those BCMs
downstream from the open circuit. It is to be understood that each
capacitor 24 is disposed within a respective BCM, and is
illustrated in FIG. 1 as being outside of each BCM only for
purposes of reference and illustration.
An EMS constructed according to principles of this invention also
includes means for protecting the control unit 22 from high-voltage
differentials between the main conductor 16 and the control unit,
and for filtering out signals other than the radio frequency
signals transmitted by the BCMs. In one embodiment, such means is a
capacitor 26 connected in line between the control unit 22 and the
main conductor 16. The capacitor serves primarily to isolate the
control unit 22 from any high-voltage differentials that may
develop. The capacitor 26 also has high-pass filter characteristics
to enable the passage of radio frequency signals to and from the
control unit. The lower cutoff frequency of the high-pass filter is
determined by the values of frequencies being used for radio
frequency communication, and is set at approximately 30 kilohertz
in this embodiment.
An EMS constructed according to principles of this invention also
includes means for preventing passage of high-frequency signals
from other electrical devices connected to the electrical system by
the main conductor 16, and for preventing the leakage of radio
frequency signals from the EMS to the power handling desire or
motor controller. Such means are used to ensure that the radio
frequency signals generated by each BCM is transmitted to the
control unit, and to ensure that each radio frequency control
signal generated from the control unit to each BCM, free from
high-frequency interference or signal leakage. In one embodiment,
such means are used to eliminate the passage of high-frequency
signals generated by the motor controller 12 to the main conductor
16, and to prevent the passage of the radio frequency signals from
the main conductor to the motor controller. In a preferred
embodiment, the means for preventing the passage of high-frequency
signals from the motor controller, and for eliminating radio
frequency leakage by the motor controller, includes isolation bands
28 that are made from a signal filtering material. The bands 28 are
each placed around the main conductor 16 adjacent each connection
point to the motor controller 12.
In a preferred embodiment, the bands 28 are made from ferrite
beads, which are designed to filter out or prevent the passage of
high-frequency signals above about 100 Kilohertz from the motor
controller 12 into the main conductor 16. The ferrite beads also
prevent transmission of the EMS radio frequency signal into the
motor controller to eliminate signal leakage.
Referring still to FIG. 1, the electrical system of the
electrically powered device or vehicle includes a battery charger
29. The EMS is illustrated as being adapted for connection with a
battery charger 29. In one embodiment, the battery charger 29 can
be disposed on board the electric vehicle and include DC power
leads 30 that are electrically connected to the battery pack via
the main conductor 16. Bands 28, identical to those discussed
above, are placed around the leads 30 adjacent each connection
point to the charger 29 for the same purposes previously discussed.
The charger 29 includes a power lead 31 that is adapted to
facilitate connection with an external AC power source. In certain
embodiments, the control unit 22 is manufactured as part of the
battery charger 29.
In an alternative embodiment, the battery charger 29 is disposed
off board of the electric vehicle, and includes DC power leads 30
that are adapted to facilitate temporary electrical connection with
the main conductor 16 when charging the battery pack. The temporary
electrical connection can be made by using conventional attachment
techniques such as by using releasible hard wire-type connections,
inductive coupling and the like. Like the on-board charger
embodiment, bands 28 are placed around the power leads 30 adjacent
the connect point to the off-board charger. The off-board charger
can be part of a battery pack charging system maintained at a
vehicle repair facility, at a public or private parking garage and
the like.
The EMS includes a second control unit 33 located off board of the
vehicle. The second control unit or off-board control unit is
attached to a lead 30 of the on-board or off-board charger 29. The
off-board control unit 33 is configured in the same manner as the
control unit 22 described above and below, to communicate with the
on-board control unit 22 and/or the BCMs by radio frequency
transmission via wired, radio, or inductive signal coupling.
Specifically, the off-board control unit 33 serves to monitor
battery operating parameters and control one or more BCM to
regulate the operation of one or more battery, or battery cell,
when charging the battery pack. Additionally, as described in
better detail below, the off-board control unit is used to retrieve
battery operating performance information, stored in the on-board
control unit 22, during charging or during other type of battery
pack servicing or maintenance. A capacitor 35, identical to the
capacitor 26 discussed above, is placed in line between a radio
frequency transmission line from the off-board controller and the
lead 30.
The off-board control unit 33 is adapted to accommodate connection
with a user interface 37 to facilitate programming the on-board
control unit and accessing information stored in the on-board
control unit. In certain embodiments, the off-board control unit is
manufactured as being part of the off-board charger, and is
programmed to receive downloaded battery performance information
from BCMs or the control unit and regulate battery operating
parameters during battery pack charging.
Referring now to FIG. 2, each BCM 18 includes monitoring element(s)
or sensor(s) 32 that are configured to measure or monitor a
designated power source or battery operating parameter. In one
embodiment, each BCM 18 includes two monitoring elements 34 and 36
for measuring the voltage and temperature of a respective battery.
Each monitoring element 32 is configured to operate on 12 volt DC
power and provide an analog signal output in the range of from
about zero to five volts DC. In an embodiment where a BCM includes
more than one monitoring element 32, an analog multiplexer 38 is
provided that is configured to accommodate the analog signal
outputs from each monitoring element, e.g., the voltage monitoring
element 34 and the temperature monitoring element 36. A preferred
analog multiplexer 38 is a single pole double throw type switch.
Operation of the multiplexer 38 is controlled by a controller in
the BCM, discussed in greater detail below.
Each BCM 18 includes a voltage to frequency convertor 40, which is
configured to receive an input analog signal from the analog
multiplexer 38 and convert the analog signal to a digital signal
that is configured as a particular series of voltage pulses and the
like. In one embodiment, the convertor 40 is configured to receive
an input analog signal of from zero to five volts DC and convert
the input signal to a pulsed signal of either no output (also
referred to as logic 0) or an output of about five volts (also
referred to as logic 1), wherein the voltage information is encoded
as the frequency of a pulse train.
Each BCM 18 includes a radio frequency (RF) transmitter 42 that is
configured to modulate the pulsed signal output from the convertor
40. The radio frequency transmitter 42 can be a broadband
transmitter, such as an frequency shift keying (FSK) transmitter.
An output from the RF transmitter 42 is connected to the main
conductor 16 so that the radio frequency signal is transmitted via
the main conductor 16 to the control unit 22. In one embodiment,
the RF transmitter is configured to transmit a broadband radio
frequency signal of approximately 5.5 megahertz. Operation of each
RF transmitter is controlled by a timer circuit in a controller of
the respective BCM.
Each BCM 18 includes means for eliminating the passage of
high-frequency signals outside of the range of radio frequency
signals transmitted by the EMS. In one embodiment, such means is in
the form of an input filter 44 is connected in line between the
main conductor 16 and an RF demodulator in the BCM. In one
embodiment, the input filter 44 that is configured as a 4.5
megahertz bandpass filter to prohibit the passage of radio
frequency signals above or below approximately 4.5 megahertz and,
is configured as a common-mode rejection filter to thereby reduce
or eliminate possible signal interference.
A radio frequency signal sent from the control unit 22, via the
main conductor 16, is transmitted to each BCM at a broadband radio
frequency of approximately 4.5 megahertz, depending on the
particular digital control signal. Each radio frequency control
signal transmitted by the control unit is made up of an address
string to one or more BCM, and a particular command string. Each
BCM 18 includes an RF demodulator 46 and the like that is
configured to receive a radio frequency control signal transmitted
from the control unit 22 and demodulate it to a digital signal. In
one embodiment, the RF demodulator 46 is capable of receiving the
broadband radio frequency control signal of 4.5 megahertz and
converting it to a digital signal zero or five volts.
Each BCM 18 includes means for decoding the digital control signal
that is received from the RF demodulator 46. In one embodiment, the
decoding means is a post office code standardization advisory group
(POCSAG) decoder, which is also known as a consultative committee
international radio (CCIR) paging code No. 1. The POCSAG decoder 48
is capable of identifying whether the digital control signal, i.e.,
the addressed command string, that is received is addressed to one
or more particular BCM 18. If a correctly addressed code is
recognized, the POCSAG decoder transfers the remaining portion of
the signal, i.e., the command string, to a controller 50. If an
incorrectly addressed code is received by the POCSAG decoder, the
remaining command string is not passed on to the controller 50. As
mentioned above, each BCM 18 can be configured to recognize one or
more address code so that groups of more than one BCM can be
controlled simultaneously if desired.
In one embodiment, the controller 50 is configured to accept the
input digital control signal, i.e., the command string, and to
identify whether it matches a predetermined command. In a preferred
embodiment, the controller 50 performs simple pattern matching to
determine whether or not the command string corresponds to one of
the following six predetermined commands: (1) shunt and transmit
voltage; (2) shunt and transmit temperature; (3) shunt and do not
transmit; (4) transmit temperature; (5) transmit voltage; and (6)
do not shunt and do not transmit. Once the controller 50 has
identified a particular command string, it outputs a control signal
to activate a particular device. In one embodiment, the control
signal may be sent to activate one or more device(s) comprising the
RF transmitter 42, the analog multiplexer 38, and one or more
control device(s), discussed below. The controller 50 can also be
programmed to cause the battery control module to perform battery
monitoring and controlling functions in response to internal
criteria, rather than in response to control signals from the
control unit 22.
As shown in FIG. 2, an output from the controller 50 is connected
to the RF transmitter 42, to operate the transmitter in response to
a particular command string received from the control unit 22, such
as commands 1-2 and 4-5 above. The output from the controller 50 is
also connected to the analog multiplexer 38, to switch between the
voltage and temperature monitoring elements 34 and 36 in response
to a particular command received from the control unit 22, such as
1-2 and 4-5 above.
The output from the controller 50 can also be connected to one or
more control element or device to effect some change in one or more
operating parameter(s) of the respective battery or battery cell
monitored by the BCM 18. In one embodiment, the control device is a
bypass shunt switch (BSS) 52. The BSS 52 is positioned across the
terminals of the respective battery and may be configured to
discharge a respective battery within the battery pack through a
shunt resister. In a preferred embodiment, the BSS 52 is configured
to discharge a respective battery upon activation by the controller
in response to a command received from the control unit, such as
commands 1-3. The BSS does this by drawing current away from the
battery using one or more resistors and the like. Activating the
BSS in one or more BCM to discharge one or more batteries in a
battery pack may be desired, for example, to control the voltage
output of each individual battery in the battery pack to achieve
battery equalization, or to protect a battery from harmful effects
of overcharging.
Referring now to FIG. 3, the EMS control unit 22 includes an RF
receiver 56 having an input connected to the main conductor 16, via
the in-line capacitor 26, as shown in FIG. 1. The RF receiver 56 is
a broadband receiver configured to receive the broadband radio
frequency signal transmitted by the RF transmitters of each of the
BCMs. In one embodiment, the RF receiver 56 is configured to
receive a broadband radio frequency signal of approximately 5.5
megahertz. The RF receiver 56 also demodulates the received radio
frequency signal into a digital voltage signal, for example, in one
embodiment from zero to five volts DC.
Output from the RF receiver 56 may either be connected directly to
a microcontroller unit 58, or may alternatively be connected to the
microcontroller unit 58 via a digital multiplexer 60 or other
digital switch. The multiplexer 60 is operated by the
microcontroller unit 58 to select from one of a number of different
input signals to be processed by the microprocessor unit. In one
embodiment, a multiplexer 60 is used to select between an output
signal from the RF receiver 56 and input signals from other
electrical devices within the vehicle, e.g., input signals from the
motor controller to provide voltage, current, temperature, and
charging status information.
The microcontroller unit 58 is configured to operate off of
available power, such as 12 volts DC when used in an electric
vehicle, and includes a microprocessor board (not shown).
Alternatively, the microcontroller unit can operate from an
internal source of power, from vehicle power external from the
battery pack, from solar power and the like. The microprocessor
board is configured to accommodate a number of different input
signals that include the digital voltage signal output from the RF
receiver 56. The microprocessor board is programmed to receive the
signal output from the RF receiver, and additionally store the
received information in a SRAM or EEPROM. The control unit 22 is
adapted to accommodate connection with a user interface to
facilitate programming the microprocessor board and to gain access
to information stored in the microprocessor SRAM. Information
stored in the microcontroller unit 58 can be retrieved at a later
time for purposes of diagnostic evaluation and the like. Such
stored information includes the performance history of each battery
in a battery pack, or each battery cell of batteries in a battery
pack, over the service life of the battery or battery pack, or
within the servicing interval of the same. In certain embodiments
of the invention, such battery performance history is retrieved by
the off-board control unit 33 during vehicle maintenance or battery
pack servicing to provide important information that may indicate
the mechanism or reason for a particular battery-related
failure.
The signal output received from the RF receiver 56, i.e., battery
operating parameter information transmitted by each BCM, is
evaluated by the microprocessor according to one or more control
system programs. In various embodiments, the microprocessor uses
control, pattern recognition, artificial intelligence, fuzzy logic,
neural network, or other analysis and control techniques to
interpret the information received from each of the BCMs and/or
generate a control response. Once the received information is
evaluated, the microprocessor effects one or more process steps
that include generating one or more particular command.
In a preferred embodiment, the microprocessor unit 58 generates one
or more of the six commands discussed above. Each command is
configured in the form of a serial digital control signal
comprising series of zero or five volt bits. Each command string is
accompanied by one or more address, configured as an additional
series digital signal that corresponds with one or more address of
a particular BCM. In this manner the control unit 22 is able to
transmit control signals to one or more particular BCM. Although a
particular method of tagging or addressing the command string to
one or more designated BCM has been specifically disclosed, it is
to be understood that other techniques of tagging or addressing the
command string can be used, such as by analog tagging techniques,
other digital tagging techniques, or by using multiple channels of
radio frequency signals.
The output signal from the microcontroller unit 22, i.e., the
addressed command pulse signal, is routed to an RF transmitter 62.
The RF transmitter 62 is preferably a broadband transmitter similar
to the RF transmitters in each BCM. The RF transmitter 62 takes the
serial digital signal and transmits a broadband radio frequency
signal of approximately 4.5 megahertz, depending on whether a
signal of one or zero is received, respectively. An output from the
RF transmitter 62 is connected to the main conductor 16 via the
in-line capacitor 26.
In addition to providing a control signal to each of the BCMs, the
microprocessor unit 22 is also configured to perform other
functions such as: (1) monitoring a current state of charge for the
battery pack and transmitting the same to a fuel gauge indicator;
(2) controlling the operation of a ventilation fan in a battery
compartment of the vehicle; (3) controlling the operation of
auxiliary electrical devices, e.g., passenger compartment heating
and cooling functions, to reduce the power routed to such devices
or load shed when conditions call for battery conservation; and (4)
activating a maintenance warning light to indicate when one or more
battery or battery cells within a battery pack need replacement or
servicing.
In a preferred embodiment, an EMS constructed according to
principles of this invention operates to monitor the performance of
individual batteries in a battery pack, or individual battery cells
in batteries making up a battery pack, to achieve battery charge
equalization. Battery charge equalization refers to controlling the
state of charge of each battery in a battery pack so that each
individual battery is charged to the same degree as other batteries
in the pack. For example, if one battery in a battery pack is
relatively weaker than the remaining batteries, the weak battery
will be selectively charged for a longer period or more frequently
than the other batteries so that it does not have the effect of
weakening the overall performance of the pack. As another example,
if one battery in a battery pack is relatively stronger than the
remaining batteries, the strong battery will be selectively
discharged so that it does not have the effect of reducing the
charging time or frequency for the remaining batteries. Battery
charge equalization, therefore, improves battery pack service life
because each battery in the battery pack is monitored and
controlled individually to perform equally.
EMSs constructed according to this invention have several
advantages when compared to existing wired-type systems. One
advantage is the reduced material cost of the EMS system due to the
elimination of extra wires, wiring harnesses, and installation
associated with such wires. Another advantage is that the use of
the EMS eliminates the need for high-voltage isolation components,
needed to monitor and control signals with widely differing base
voltages. Another advantage is the weight savings realized by the
EMS due to the elimination of extra wires, wiring harnesses, and
high-voltage isolation components. Another advantage is that the
EMS is safe to install because it does not include any components
or modules that are connected with voltages greater than 12 volts
DC. Another advantage is that the EMS is more reliable and has a
potentially longer service life than wired-type systems because it
lacks the most vulnerable element of those systems; namely, exposed
signal wires near the battery.
Still another advantage of EMSs of this invention is the modular
design of components, which allows for extremely flexible and
robust system operation. For example, single failures in one BCM or
an open circuit in a battery do not disable the entire system
because other BCMs are still able to transmit information to and
receive control signals from the control unit via radio frequency
transmission. The modular construction also facilitates easy
removal of an improperly operating or nonfunctioning BCM from the
system as well as replacement with a repaired, new or upgraded BCM.
Further, modular construction facilitates the introduction of
additional BCMs or other system modules into the system by simply
reprogramming or instructing the control unit.
The modular construction of the EMS allows for the installation of
system components inside of existing electrical system components,
e.g., the installation of a BCM within a battery housing, thereby
allowing them to be made by the manufacturers of such electrical
system components. For example, the control unit can be
manufactured into the motor controller or into an on-board battery
charger. Incorporating the EMS components into existing electrical
system components is advantageous because it could further reduce
the cost of the EMS, increase the reliability of the EMS, reduce
the space requirements for the EMS, increase EMS flexibility, and
allow the EMS to cooperate directly with the motor control or
battery charger.
Although a specific embodiment of the EMS has been described and
illustrated herein, many modifications and variations will be
apparent to those skilled in the art. For example, an EMS within
the scope of this invention comprises means for facilitating the
transfer of radio frequency transmissions to and from the control
unit and each BCM by other than by conductive radio frequency
transmission via the main conductive path, e.g., the main
conductor, in an electrical system, such as by nonconductive
methods, e.g., an antenna system, remote from the main conductor.
As another example, the EMS can use radio frequencies other than
those specifically described above for purposes of transmitting
information from the BCMs and control signals from the control
unit. Additionally, the information and control signals generated
by the EMS can be transmitted, via radio frequency, using analog
rather than digital transmission methods.
Accordingly, it is to be understood that within the scope of the
appended claims the EMS according to principles of this invention
may be embodied other than as specifically described herein.
* * * * *